TrueTone

一个大的频率范围内精确的音调发生器，对数刻度，额外的选项。

Test your hearing! Find out the real limits of your phone audio! Annoy your friends (at your own risk of course)! Learn and teach about how different tones sound like! Generate exact references tones! All this and more in this app.

Features:

-can cover a frequency range from 10Hz to 20kHz (actual range dependent on your audio hardware),

-exact tone generation, no messy approximation,

-*new* toggle for logarithmic slider,

-multiple wave types! Choose from sine, square, sawtooth and triangle,

-setting the frequency down to a single Hertz (and not 10 Hz, like in some other applications),

-connect external speakers to your device for even better sound and frequency range!

-Easy way to contact the developer: just press the "Report Bug/Suggest Feature" button and type away!

-option to keep the app running indefinitely,

-adapted for accessibility applications - easier to use for the vision-impaired.

Note: you can set the volume simply by using the buttons on your phone.

Internet permissions are needed for:

-ads (this is an ad-supported ad),

-feedback (you can report a bug or suggest a feature directly from the app),

-ANONYMOUS usage statistics.

Wakelock permission is needed for the "keep alive" option.